The present invention relates to a magnetic writing/reading apparatus for writing data on a magnetic tape contained in a tape cassette and reading data from the magnetic tape. The present invention in particular relates to a magnetic writing/reading apparatus used as a so-called streaming tape drive or streamer described below.
Such a streamer is used as an auxiliary information-storing device for backing up a main information-storing device such as a hard disc drive employed in a computer system. A magnetic tape is employed in such an information storing device as the streamer. The magnetic tape is contained in a tape cassette and wound on a pair of tape reels. The tape cassette further contains a driving roller linked with the tape reels. The roller is driven while the tape cassette is loaded in the device so that the magnetic tape runs as a result of the reels being driven by the driven driving roller. As a result, an arbitrary part of the magnetic tape may be accessed in a data writing/reading operation of the information storing device.
In such a kind of information storing device, an idler roller is provided for driving the above driving roller in the tape cassette while the idler roller is pressed onto the driving roller. The idler roller is driven by a motor, rotation of which is controlled by a servomechanism using a signal, a frequency of which is proportional to the rotation speed of the motor.
The present applicant propoes a new type of a magnetic writing/reading apparatus preferably for use with a tape cassette in a tape driving mechanism having a rotary magnetic head.
An example of a prior art magnetic writing/reading apparatus having a rotary magnetic head instead of a fixed head is taught in Japanese patent application No. 4-2286370 will now be described with reference to FIG. 1. FIG. 1 shows a plan view of this example of the magnetic writing/reading apparatus. A magnetic writing/reading apparatus 11 operates with a suitable type of a tape cassette 12 to be loaded therein. The magnetic writing/reading apparatus 11 has an arrangement as generally described below. The apparatus 11 comprises a tape driving mechanism 13, a rotary magnetic head 14, and a loading mechanism not shown in FIG. 1. The magnetic head 14 is rotated by means of a head motor 14a. The loading mechanism is used for loading the tape cassette 12. The tape driving mechanism 13 has a construction in which a wheel 15a mounted on a shaft of an idler-driving motor 15 is linked with an idler roller 18 through a belt 18a. While the tape cassette 12 is loaded in the device, the rotation of the idler roller 18 causes a magnetic tape 12a contained in the tape cassette 12 to run. This is because the idler roller 18 comes in contact with a driving roller 20, provided in the tape cassette 12, while the cassette 12 is loaded in the apparatus, the rotation of the driving roller 20 resulting in running of the magnetic tape 12a as described below.
Guidance grooves 19a and 19b are respectively formed in side walls of the tape cassette 12 as shown in FIGS. 1, 2A and 2B.
FIGS. 2A and 2B show perspective views of the front part of the tape cassette 12, and FIGS. 3A and 3B show a plan view and a front elevational view thereof respectively. In FIG. 3A, even the internal construction is indicated, by solid lines to make it easier to understand the following description thereof. The tape cassette 12 comprises a box-shape housing 21 as shown in the drawings. The above guidance grooves 19a and 19b formed in the side walls of the cassette are used for guiding a direction along which the cassette is inserted into the magnetic writing/reading apparatus 11. Locking cutouts 19c and 19d are formed at the bottom edges of the grooves 19a and 19b respectively. The locking cutouts 19c and 19d are used for locking the cassette 12 in the loaded position in the magnetic writing/reading apparatus 11. An opening 22 is formed in the front wall of the cassette 12, which opening 22 is exposed by opening a lid 23 which closes the opening 22. The lid is hinged so as to be movable to open and close the opening 22. The lid 23 is opened in response to the insertion of the cassette 12. Another opening 24 is formed in the front wall of the cassette 12, which opening 24 is adjacent to the above opening 22. This opening 24 exposes the above driving roller 20 which is rotatably supported on a top plate 21a of the housing 21 as shown in FIGS. 2A, 2B and 3B.
The lid 23 closes the opening 22 while the cassette 12 is not loaded in the magnetic writing/reading apparatus 11. The lid 23 accordingly protects the internal components of the cassette 12, the components including the magnetic tape 12a. The above rotary magnetic head 14 is inserted in the opening 22 so as to make the head access the tape 12a. When the cassette 12 is loaded into the magnetic writing/reading apparatus 11, the lid 23 rotates in a direction shown by an arrow R in FIG. 2B so as to expose the opening 22 and as a result expose the magnetic tape 12a, as described below.
A pair of reels 25 and 26 are respectively rotatably supported in the housing 21 and the magnetic tape 12a is wound on the reels 25 and 26 as shown in FIG. 3A. Further, in the housing 21 of the tape cassette 12, a driving belt 29 is wound on and extends among guidance rollers 27 and 28 and the above driving roller 20. The driving roller 20 is provided at the front side of the housing 21 while the guidance rollers 27 and 28 are provided at the rear side of the housing 21 as shown in FIG. 3A. Further, the driving belt 29 is guided so that the belt 29 is pressed onto the peripheral surface of the magnetic tape 12a wound on the reels 25 and 26 as shown in FIG. 3A. In this arrangement, the driving belt 29 rotates as a result of being driven by the rotating driving roller 20 and, as a result, drives the reels 25 and 26 in a predetermined tape winding direction.
The loading into and ejecting from the magnetic writing/reading apparatus 11 of the cassette 12 are performed manually. In the loading operation, the cassette 12 is manually inserted into the magnetic writing/reading apparatus 11 while the guidance grooves 19a and 19b are fitted into respective guidance plates 16a and 16b provided in the apparatus 11. The ejecting operation is performed so that the cassette 12 is either directly withdrawn from the apparatus 11 manually or pushed out through an ejection mechanism, manual pressing of an ejecting button driving the ejection mechanism.
Problems may occur in the use of such a magnetic writing/reading apparatus as the above apparatus 11, which problems are described below. In the apparatus, the loading and ejecting operations are performed in a substantially manual manner as mentioned above, these operations being performable without regard to which sort of operation is being performed in the magnetic writing/reading apparatus. That is, the loading and ejecting operations can be performed even though the magnetic writing/reading apparatus is in a state in which data is written into or read from a magnetic tape. As a result, the apparatus and/or data stored in the magnetic tape may be damaged.
Further, if the magnetic writing/reading apparatus has an arrangement for manually withdrawing the loaded cassette so as to eject it, a part of the loaded cassette has to be projected from the apparatus, this projected part being grasped by hand when the cassette is being withdrawn from the apparatus. In such an arrangement, some sorts of dust present outside, for example, may badly influence the apparatus and/or the cassette.